Cold liquid container and elements for use in same

ABSTRACT

951,179. Storing liquefied gases. CONCH INTERNATIONAL METHANE Ltd. Sept. 7, 1962 [Oct. 30, 1961], No. 34283/62. Heading F4P. The inner shell of a double-walled liquefied gas storage container 22, Fig. 4, having heat insulation material e.g., balsa wood or quippo between the shells is formed of a plurality of panels 10 of sheet material e.g. stainless steel, copper, brass, aluminium or glass fibre-reinforced plastic material bonded together along overlapping portions of their edges 18, Fig. 3, to form an impermiable membrane and each panel is provided with a central annular embossment 14 from which radiate linear embossments 16 extending to the edges 18 and serving to accommodate thermal expansion stresses. Each vertical membrane is supported by studs 21 embedded in the insulation 24 and by rods 23 welded to the inner face of the outer shell 26. In a modification the upper end of each vertical membrane is bent over and is supported by the upper portion of the insulation.

' Dec. 21, 1965 w. R. UPTHEGROVE 3,224,621

COLD LIQUID CONTAINER AND ELEMENTS FOR USE IN SAME Filed Oct. 30, 1961 2 Sheets-Sheet 1 13 I0 D 6 l llJiIZzam E. Wihegmus F I G. 5 BY wzw Dec. 21, 1965 w. R. UPTHEGROVE 3,224,621

GOLD LIQUID CONTAINER AND ELEMENTS FOR USE IN SAME Filed Oct. 30, 1961 2 Sheets-Sheet 2 FIG: 4-

INVENTOR. William R. Upiheyrm/e M/ZQ MM aff'ys United States Patent COLD LIQUID CONTAINER AND ELEMENTS FOR USE IN SAME William R. Upthegrove, Norman, Okla, assignor to Conch International Methane Limited, Nassau, Bahamas, a corporation of the Bahamas Filed Oct. 30, 1961, Ser. No. 148,563 2 Claims. (Cl. 220-9) This invention relates to improvements in vessels used for the storage of liquids having a temperature differing widely from ambient temperature and it relates more par ticularly to a storage facility of large capacity for cryogenic materials. The invention is concerned with improvements in insulated vessels of the type comprising an insulated storage chamber lined with a membrane of a fluid and vapor impervious material which is insensitive to the temperature of the liquid in contact therewith whereby the membrane, which rests upon the insulation for support, represents the means by which the liquid is retained in the storage space or vessel.

Natural gas may be taken as representative of a material which is capable of liquefaction and which is available in large supply in certain areas while being deficient in many others. In such instances, it is desirable to effect distribution of the gas by transmission from the area of plentiful supply to areas where deficiencies exist. Where such areas are connected by land, the gas can be transmitted through suitable pipe lines. However, when the areas are separated by large bodies of water or where the areas are separated by great distances, pipe line transmission may become impractical.

It is known that natural gas is reduced in volume in the ratio of U600 when converted from a gaseous state to a liquefied state at equivalent pressure. As a result, more efficient utilization can be made of transportation space when the gas is transported and/or stored in a liquefied state such that it becomes practical to liquefy the gas at the source of plentiful supply for storage or transportation in the liquefied state to the areas where the deficiencies exist for subsequent reconversion to the gaseous state for use.

For practical operation, it is desirable to provide for storage or transportation of liquefied gas in tanks of large capacity. This limits the operation to storage or transportation in structures maintained at about atmospheric pressure or slightly above. Methane, which represents the principal component of natural gas, has a boiling point of about 258 F. at atmospheric pressure. Thus, liquefied natural gas, which is representative of one of the gases capable of liquefaction, storage and transportation in means embodying the practice of this invention, would be housed at a temperature below about 240 F. to 258 F., depending somewhat upon the amount of heavier hydrocarbons in the gas.

Maintenance of the liquefied gas at such extremely low temperatures presents a number of problems from the stand-point of the materials employed, and the insulation to prevent heat loss which otherwise would cause excessive loss by vaporization of liquefied gas.

One of the major problems in the construction of a membrane tank of the type described resides in the need to provide for independent movement between the membrane and its support without disengagement between the membrane and support. Such independent movement will be occasioned by reason of the differences in expansion and contraction between the material making up the membrane and the material making up the support and by reason of the wide temperature changes that occur from the time that the tank is at ambient temperature or empty and the times that the walls are wet with the cold liquefied gas. Independent movement by reason of ex pansions and contractions will occur even when the ma terials making up the membrane and the support havi similar coefiicients of expansion and contraction. Sucl independent movement between the membrane and the supporting insulation occurs because the supporting in sulation is discontinuous and each independent segmen can uniformly contract or expand in the plane of the liquid wall whereas the membrane is continuous anc should maintain approximately fixed gross dimensions As a result, any local thermal contraction of the membrane must be counteracted by an equal expansion in the same direction of the adjoining membrane material.

It is an object of this invention to produce and to provide a method for producing an insulated structure for housing cryogenic materials or materials having temperatures differing widely from the ambient temperature and it is a related object to produce a membrane tank for use in the storage of such cryogenic materials and wherein the membrane is capable of expansion and contraction movements relative to the insulated structure while relying upon the latter for support, and for the restraint of hydrostatic and other forces normal to the plane of the membrane.

These and other objects and advantages of this invention will hereinafter appear and for purposes of illustration, but not of limitation, embodiments of the invention are shown in the accompanying drawings in which:

FIG. 1 is a top plan view of a modular panel embodying the featues of this invention;

FIG. 2 is a side elevational view of the panel of FIG. 1;

FIG. 3 is a top plan view showing a plurality of the panels of FIG. 1 in their joined relationship to form a continuous lining;

FIG. 4 is a schematic sectional elevational view through an insulated storage tank showing a means for mounting the panels as a lining therein;

FIG. 5 is a schematic sectional view of a fragmentary portion of a tank illustrating another means for mounting the lining.

The concepts of this invention reside in the construction of a modular panel of the membrane material which can be joined together with other similar panels in sideby-side and in end-to-end relation to form a continuous membrane mounted as a lining on the inner surfaces of the insulated structure whereby the membrane comprises a housing for the cold liquid and which is capable of expansion and contraction due to temperature change While relying upon the insulated structure for support, and for the restraint of hydrostatic and other forces normal to the plane of the membrane.

To permit joinder of the panels into a continuous membrane which relies upon the insulation or like structure for support and to permit independent movement between the continuous membrane and its discontinuous support responsive to expansions and contractions, it is a fundamental concept of this invention to construct the modular panels with embossments so conceived and arranged as to interrupt any possible lines of force developed in the plane of the membrane by reason of loading and thermal expansion and contraction and to permit easy, elastic, lateral expansion or contraction in the vicinity of the embossed pattern to relieve those forces without destroying the impervious nature of the membrane.

The modular panels are preferably formed to a shape which permits a plurality of panels to be joined in sideby-side and in end-to-end relation to form a continuous lining. For this purpose, use can be made of panels of polygonal shape but its preferred to make use of a panel 10 of rectangular shape, as illustrated in FIGS. 1 and 2 of the drawings. The panel is formed of a sheet material having a relatively flat body portion 12. Embossments are formed in the panel, as by a drawing or stamping operation, to provide a ring 14 in the form of a circular or oval shape in the central portion of the panel with other embossments 16 extending radially outwardly as spokes from the periphery of the ring to the edges 18 of the panel.

In the preferred form, the embossed spoke sections 16 are arranged at about right angles to each other to extend outwardly from the ring to bisect the edges of the panel. Instead of arranging the embossments to bisect the edges, the embossments can be arranged to extend from the ring to the corners of the panel or the embossments can be arranged to extend from the ring at angles of about 45 apart to extend both to the corners and to bisect the edges.

The embossments, which can extend either forwardly or rearwardly from the body portion, can be either curvilinear or V-shaped or of other shapes in between and they should be formed to a depth at least sufficient to permit deformation in response to the development of force across the face of the panel to supply material at least in the amount of shrinkage or to take up material in the amount of expansion taking place in the panel in any direction due to temperature change. As a result, the panel or an assembly of panels will be able to retain its original dimension notwithstanding the amount or direction of contraction or expansion taking place.

Under such circumstances, the panels can be anchored at spaced apart points, preferably at flat portions, as by means of studs 20, onto the supporting insulated structure or other support while the body portion of the panel remains free of the supporting structure and is thus capa ble of expansion and contraction movements Without change in the dimension of the panel.

By way of example, using panels of the type having embossments 16 extending outwardly to bisect the edges, the panels can be arranged in side-by-side and in end-toend relation with the edges overlapping one another by a slight amount, as illustrated in FIG. 3, to bring the embossed portions of one into nesting relationship with the embossed portions of the other panels adjacent thereto. The overlapping edges of the panels can be joined by suitable joining means, such as by adhesive, welding or brazing if formed of metal, or by welding or adhesive if formed of plastic sheet stock, to etfect a sealing relationship between the panels. This will form a continuous impervious membrane as a lining about the adjacent inner wall of the insulated housing.

The lining can be supported within the insulated structure 22 as by the use of hanger rods or studs 20 having arms 21 extending into operative engagement with the insulation 24 or having rods 23 extending through the insulation for attachment to the structural wall 26 of the tank. The hanger rods preferably engage the panels at their corner intersections where the edges of the panels making up the intersection overlap to provide multiple thicknesses of a material to enhance the interconnection. Thus each panel will be joined to the insulated structure for support at each of its corner sections while the remainder of the panel is free of the insulated support to enable expansion and contraction independent of the insulated support. Instead of anchoring the panels at each of the corner sections, it will be satisfactory if the panels are anchored only intermittently at spaced sections which may be at the corners, edges or interior portions of the panels, since little, if any, lateral load will be carried solely by the lining. It will be understood that other means and methods of attachment between the individual panels and the supporting insulated structure may be employed without departing from the concepts of this invention.

Instead of anchoring the interconnected panelsi individually or in groups to the insulated support, the entire lining 28 formed of the joined panels 10 can be supported within the insulated structure along the upper edge to more or less suspend the lining as a shell or curtain over the insulation 24, as by the use of an expansible ring of the type more fully defined in US. Patent No. 2,954,- 892, or by the use of an upper edge 30 which overhangs a support 32 in the upper portion of the insulated structure in the manner of a hanger bracket, as shown in FIG. 5.

In either event, the liquid head 34 will be sufficient to urge the lining formed of the joined panels outwardly into engagement with the adjacent surface of the insulated structure for support, the shrinkage normally taking place when the metal of the panels is cooled to the temperature of the liquid in contact therewith being counteracted by the elastic or reversible deformation of the empossed portions. When the metal lining rises in temperature upon being freed of the liquid, the expansion normally taking place is satisfied by return of the embossed portions to normal dimension whereby the panel can continue to rest upon the insulated structure for support or shift away therefrom. Such deformation of the embossed portions to provide for lateral movement of the flat portions to compensate for expansion and contractions, respectively, is readily accomplished such that the lining can be supported in the manner described from the insulation or the insulated structure while relying upon the insulation for support.

The specific arrangement of embossed portions within each panel is designed to intersect the multi-directional forces in the plane of the membrane developing in the panels responsive to change in temperature. Thus it is possible to anchor the panels at spaced apart portions for support without interfering with the ability of each of the modular panels to expand or retract in response to temperature change. This minimizes the development of destructive forces. It also permits such expansions and contractions to take place without change in the overall dimension of the panels.

When, as in the preferred practice, the panels are formed of a gauge or thickness incapable of self-sufficiency under load, it is desirable to rely upon the insulation for support whereby liquid load is transmitted through the lining to the insulated structure. For this purpose, it is desirable to make use of an insulation of structural strength and dimensional stability, especially in the direction of hydrostatic load. Representative of the insulation which can be used are built-up layers or panels of balsa, Quippo, or the like highly porous woods, honeycomb insulation or panels having the pores running in the crosswise direction between the metal lining and the structurally strong, and preferably fluid and vapor impervious, outer wall.

The modular panels can be formed of any fluid or vapor impervious material which retains its strength and resiliency at the temperature conditions to which it will be exposed. For use with cryogenic liquids, it is preferred to make use of a sheet formed of a metal, such as aluminum or alloys of aluminum, copper, brass, high nickel steels or austenitic steels. Use can also be made of plastic sheet stock, glass fiber reinforced plastics, or combinations of metals and plastics such as metal-clad laminates. A lining formed of sheets having a thickness greater than 4 mils can be used but it is preferred to make use of sheets having a thickness within the range of 10 to mils.

It will be apparent from the foregoing that the basic concepts of this invention can be achieved by the use of an embossed panel construction wherein the easy deformation of the embossed patterns restricts all forces in the plane of the membrane to some acceptable value while forces normal to the membrane are transmitted to the insulated supporting structure.

It will be understood that changes may be made in the details of construction, arrangement and operation without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

1. In an insulated container for housing liquefied gas in large volume including an outer shell, an insulation layer lining the inner surface of the outer shell and an inner shell formed of a membrane of fluid and vapor impervious material which retains its strength and ductility at the cold temperatures of the liquefied gas, said shell being formed of a plurality of modular rectangular panels of thin sheet material arranged in side-by-side and in end-to-end relation and joined one to another in sealing relation along the adjacent edges to form the continuous membrane, embossments in each of said panels comprising a ring-like embossment in the central portion of the panel and linear embossments extending radially outwardly from the periphery of the ring to the edges of the panel, and means for supporting the shell of joined panels adjacent the inner face of the insulation layer, the panels being secured at the corners formed by adjacent sides to the insulation while being free of the insulation through the remainder thereof.

2. In an insulated container for housing liquefied gas in large volume including an outer shell, an insulating layer lining the inner surface of the outer shell and an inner shell formed of a membrane of fluid and vapor impervious material which retains its strength and ductility at the cold temperatures of the liquefied gas, said shell being formed of a plurality of interfitting polygonal panels of thin sheet material having corners formed by adjacent polygonal sides and arranged in interfitting relation with adjacent sides joined to one another in sealing relation along the adjacent edges to form the con tinuous membrane, embossments in each of said panel comprising a ring-like embossment in the central por tion of the panel and linear embossments extending radially outwardly from the periphery of the ring to tht edges of the panel, and means for securing the panel: at their corners only to the insulation, the panels being free of the insulation through the remainder thereof.

References Cited by the Examiner UNITED STATES PATENTS 1,859,339 5/1932 Murphy.

2,020,630 11/1935 Anderson 22063 2,100,895 11/1937 Austin 22063 2,260,393 10/ 1941 McCarthy 22063 2,876,927 3/1959 Henning 22063 2,889,953 6/1959 Morrison 2209 2,893,588 7/1959 Martin 22072 2,954,892 10/1960 Dosker 22063 2,969,162 1/ 1961 Stutske 22072 X 2,983,401 5/1961 Murphy 22010 3,030,669 4/1962 Dosker 22010 X 3,088,621 5/1963 Brown 2209 3,098,597 7/1963 Johnson et al. 22072 X FOREIGN PATENTS 1,244,448 9/1960 France.

THERON E. CONDON, Primary Examiner. 

1. IN AN INSULATED CONTAINER FOR HOUSING LIQUEFIED GAS IN LARGE VOLUME INCLUDING AN OUTER SHELL, AN INSULATION LAYER LINING THE INNER SURFACE OF THE OUTER SHELL AND AN INNER SHELL FORMED OF A MEMBRANE OF FLUID AND VAPOR IMPERVIOUS MATERIAL WHICH RETAINS ITS STRENGTH AND DUCTILITY AT THE COLD TEMPERATURES OF THE LIQUEFIED GAS, SAID SHELL BEING FORMED OF A PLURALITY OF MODULAR RECTANGULAR PANELS OF THIN SHEET MATERIAL ARRANGED IN SIDE-BY-SIDE AND IN END-TO-END RELATION AND JOINED ONE TO ANOTHER IN SEALING RELATION ALONG THE ADJACENT EDGES TO FORM THE CONTINUOUS MEMBRANE, EMBOSSEMENTS IN EACH OF SAID PANELS COMPRISING A RING-LIKE EMBOSSMENTS IN EACH OF SAID PORTION OF THE PANEL AND LINEAR EMBOSSMENTS EXTENDING RADIALLY OUTWARDLY FROM THE PERIPHERY OF THE RING TO THE EDGES OF THE PANEL, AND MEANS FOR SUPPORTING THE SHELL OF JOINED PANELS ADJACENT THE INNER FACE OF THE INSULATION ALYER, THE PANELS BEING SECURED AT THE CORNERS FORMED BY ADJACENT SIDES TO THE INSULATION WHILE BEING FREE OF THE INSULATION THROUGH THE REMAINDER THEREOF. 